A board, or "flitch", by definition has first and second opposed cut planar faces and first and second opposed waned edges. In the prior art, flitches would be scanned and sequenced horizontally, positioned in the desired skew, if any, and then clamped by feed rolls to be feed linearly into a conventional edger. Alternatively, the flitches would be symmetrically centered in the direction of flow, fed through a linear scanner, and then, in the same direction of flow, into an edger capable of skewing and laterally translating. The first approach is effective, but the system is quite expensive and the positioning of the flitch can take up time. The second approach, such as is taught in U.S. Pat. No. 4,599,929 to Dutina, works fine, but the system does not take full advantage of modern automatic controls and does not teach the requisite mechanics to do so.
Different lineal scanning and positioning methods have been used. U.S. Pat. No. 4,239,072, to Merilainen, discloses a lineal scanning and skew edging process, but does not allow for multiple saws. U.S. Pat. No. 4,449,557, to Makela, discloses a similar process to that of Merilainen '072, but lacks the ability to reduce the edgings to chips, and also does not allow for multiple saws.
U.S. Pat. No. 5,429,161 to Allard discloses a linear scanning resawing process. The apparatus positions the workpiece while the workpiece is moving by means of two pair of tandem, opposed top and bottom, clamp rollers that skew the workpiece as it is translated for resawing. This process relies on twisting the workpiece as it moves through the roller clamps. This causes skidding of the workpiece between the rollers as they are skewed. The variance in friction between different workpieces and the rollers and the difference in the direction of the rollers' axis and the direction of the workpiece as it travels through the roller clamps, may cause a margin of error that reduces the recovery percentage. It is well known in the industry that roll feed edgers are not that accurate.